How do you find out the answer? I know there are 9 in my state.
Due to gerrymandering with bizarrely-shaped districts, it can be tricky to find out which district you're in. The same zip code can include segments of 3 different districts that zigzag through the state. For example, look at the district map of Debbie Wasserman Schultz: http://wassermanschultz.house.gov/images/fl20_lg.gif
The link below can help you find your district and Congressperson. Fortunately they have a page that narrows it down by street address, in case your zip code includes multiple districts.
http://www.house.gov/representatives/find/