Assemblyman Rory I. Lancman acknowledges that he can strike some as arrogant, even irritating. But he notes that none of his financial-reform legislation could have passed in Albany without bipartisan support. And City Councilwoman Elizabeth S. Crowley knows that politicos whisper that she lacks the intellectual horsepower to keep pace in Congress. But she brushes off such talk as elitist, and proudly promotes her working-class support from police officers, firefighters and construction workers. In some ways, the major candidates vying in the Democratic primary next Tuesday in the Sixth Congressional District, which covers a diverse swath of central and eastern Queens, are all trying to prove that they are not what their reputations suggest. After all, the candidates concede there are not major differences in their views on core issues like the economy, transportation and immigration. And they also know they cannot match the three decades of incumbency or the high name recognition of the retiring legislator they hope to replace, Representative Gary L. Ackerman. So in a newly configured district, and anticipating a low-turnout election, the candidates are desperate to define who they are — and who they are not. Bruce N. Gyory, who teaches political science at the State University at Albany, said he was riveted by the contest, because he could not think of a Congressional primary for an open seat that was as wide open, or as perplexing, since Herman Badillo eked out a win over Peter F. Vallone Sr. in 1970. “I don’t think polling will be particularly helpful here,” he said. “I don’t think speculation is helpful here. I don’t see any reasonable prognostication about who will win. This is one that will be fascinating until you see the machines opened up Tuesday night.” Turnout, everyone agrees, will be crucial, with perhaps 32,000 out of 186,000 registered Democrats expected to vote. Ms. Meng, a fluent Mandarin speaker who has garnered much attention from the Asian-American media, needs a strong showing from Chinese, Korean and South Asian voters. Mr. Lancman, whose campaign believes he has the strongest field operation, is counting on support from Jewish and union voters, while Ms. Crowley, whose mailers have been praised as top-notch even by rival campaigns, is expected to run particularly well among white voters. The winner of the primary election will most likely face Daniel J. Halloran III, a Republican member of the City Council, in the November general election. The primary battle began in March, when Mr. Ackerman unexpectedly announced that he would not seek re-election. The Queens Democratic Party, led by its powerful chairman, Representative Joseph Crowley, tapped Ms. Meng, 36, to run; the reconfigured district is about 40 percent Asian-American, and if elected, she would be the first Asian-American member of Congress from New York. But after Mr. Lancman, 43, announced that he would also seek the nomination, he picked up early momentum, collecting crucial endorsements from the Working Families Party, many unions and former Mayor Edward I. Koch. He also performed strongly in candidate debates. Then came Ms. Crowley, 34, a cousin of Mr. Crowley. Despite speculation that she was a stalking-horse, urged by her cousin to siphon votes from Mr. Lancman, she insisted that she had contemplated running for higher office even before Mr. Ackerman announced his retirement. There is also a fourth Democrat on the ballot, Dr. Robert Mittman, a libertarian-leaning family doctor, who has not attracted prominent endorsements or financial support. In an interview, the low-key Ms. Meng vowed that she would be an independent force in Washington who would focus primarily on transportation, infrastructure and economic issues. “When I’m drafting or supporting legislation, no one is whispering in my ear except constituents,” she said. “I’ve never had political rabbis.” Mr. Lancman has vowed to focus on foreign policy and Wall Street reform in Washington, and has highlighted his legislative accomplishments, like helping homeowners recover legal fees in foreclosure cases. The most aggressive of the candidates, he sent out a mailer this week criticizing Ms. Meng and Ms. Crowley as being weak on counterterrorism. “We all know there are Type A personalities, and maybe I’m a Type AA personality,” he said. “I will always be a very aggressive and prepared counterbalance to any of the crazy right-wing stuff that Republicans want to put forward.” Ms. Crowley said she wanted to be a voice on women’s health issues in Washington, and dreamed of extending the No. 7 train to La Guardia Airport. She scoffed at the notion that she was a “spoiler” candidate, saying that “I guarantee I’m known better in my own district” than her opponents are in theirs. “If somebody tries to poke fun at me, I don’t get distracted,” she said. “I always try to stay on message.”