Byron Sigcho-Lopez is running to replace retiring Rep. Jesús "Chuy" García. Sigcho-Lopez’s chief of staff is running unopposed in the Democratic primary. Promising to fight back against the Trump administration, a Chicago alderman has officially announced his run for Congress. What we know:25th Ward Alderman Byron Sigcho-Lopez says he’s running as an independent to replace retiring U.S. Representative Jesús "Chuy" García. Dig deeper:Meanwhile, Sigcho-Lopez’s chief of staff, Patty Garcia, is running unopposed in the Democratic primary, which is scheduled for March 17.