Two Chicago aldermanic challengers, Susan Sadlowski Garza and Milagros "Milly" Santiago, have defeated their incumbent rivals in their respective 10th and 31st ward races, according to the last unofficial vote count released Tuesday by the Chicago Board of Election Commissioners.

All votes have been counted in the aldermanic races, and the election numbers will become official on Thursday. The totals are expected to remain the same by then.

According to the unofficial numbers, Garza beat out incumbent Ald. John Pope (10th) by 20 votes in the far Southeast Side aldermanic race. There could be a recount in the 10th Ward race, however, as both campaigns have filed court documents to challenge the election results. 

In the 31st Ward on the Northwest Side, incumbent Ald. Ray Suarez lost to challenger Santiago by 79 votes. Neither campaign has submitted official petitions to contest the election results.  

In other contentious aldermanic races, Ald. Howard Brookins (21st) and Michele Smith (43rd) retained their respective council seats, the unofficial election numbers show.