It's the Illinois 15th. I had to look this up, but the congressman was Tom Ewing, who retired in 2000, and his son was Sam.
Yes, Tom Ewing. His son was a car dealer, right? I still think that had Tom Ewing dropped out of the race the day of the filing deadline and his son had filed immediately, he would have had pretty much a free ride both in the primary and the general (unless I'm confused, Tim Johnson beat the Democrat Kelleher in the general by like only 2%).