More than two dozen candidates filed Monday evening to run for former Rep. Rahm Emanuel’s (D) North Side Chicago seat. Alderman Patrick O’Connor (D) appears to have filed at the last minute, according to the state Board of Elections. O’Connor — a heavyweight among Chicago politicians and a close ally of Chicago Mayor Richard M. Daley — was supposedly on the fence about running for Congress unless he had the mayor’s backing. His entrance into the race drastically changes the primary field to replace Emanuel. Other top Democrats in the contest include state Rep. Sara Feigenholtz, state Rep. John Fritchey and Cook County Commissioner Mike Quigley. Fifteen Democrats filed to run to succeed Emanuel, who stepped down earlier this month to become White House chief of staff. Democratic candidates were required to turn in at least 927 signatures to the Board of Elections by 6 p.m. EST Monday in order to get on the ballot. The special election primary is scheduled for March 3, and the special general election will be held April 7, although the winner of the Democratic primary is all but certain to be the district’s next Representative. Quigley’s campaign released a polling memo Monday afternoon showing he was most well-known with 39 percent name identification. The Anzalone Liszt Research poll also showed Quigley leading the Democratic field with 19 percent to Feigenholtz’s 11 percent and Fritchey’s 8 percent. But when O’Conner was included, Quigley’s edge fell to 14 percent to Feigenholtz’s 10 percent. In that ballot test, O’Connor received 8 percent and Fritchey 7 percent. The Jan. 8-13 poll sampled 500 likely Democratic primary voters. The margin of error was 4.4 points.