Chicago ? A longtime Republican district fell to the Democrats on Saturday when a scientist snatched former House Speaker Dennis Hastert’s congressional seat in a closely watched special election.

Democrat Bill Foster won 52 percent of the vote compared to 48 percent for Republican Jim Oberweis. With 564 of 568 precincts reporting, Foster had 50,947 votes to Oberweis’ 46,125.

Foster’s special election win means he will fill the remainder of Hastert’s term, which ends in January. The two will square off again in November, for a new, full term.

The 66-year-old Hastert, who lost his powerful post as speaker when Democrats took control of Congress, resigned late last year.