Four incumbents will be seeking reelection Tuesday in San Diego County congressional districts, while Rep. Duncan Hunter's son is looking to keep his father's seat in the family.

Duncan D. Hunter is running to succeed his father, an El Cajon Republican and chairman of the House Armed Service Committee who announced he was vacating the seat after more than 25 years amid a failed presidential bid last year.

The younger Hunter, a Marine Corps captain and Iraq war veteran, is being challenged by Democrat Mike Lumpkin, a retired Navy Seal commander, in the heavily Republican 52nd Congressional District.

The only local congressional race in which an incumbent faces a slight chance of loosing his seat is in the 50th District, where Rep. Brian Bilbray, R- Carlsbad, is being challenged by Democrat Nick Leibham.

Leibham, an attorney, has the considerable support of the Democratic Congressional Campaign Committee, which placed him on its "Red-to-Blue" list of districts it is targeting to change from Republican to Democrat.

Both parties have released polls with differing outcomes.

A poll conducted for Leibham shows him within 2 points of Bilbray. Bilbray's poll has him winning by 13 points.

Bilbray is seeking his second term. He replaced disgraced former Republican Rep. Randy "Duke" Cunningham, who is serving an eight-year prison term for taking bribes from defense contractors.

The district includes most of the coastal communities of North County, where Republicans outnumber Democrats by 10 percent.

In the three other San Diego County congressional districts, it is unlikely the incumbents will lose their seats.

In the 49th Congressional District, incumbent Rep. Darrell Issa, R-Vista, is being challenged by Democrat Robert Hamilton, a businessman. The district includes parts of Riverside County and much of Northern San Diego County, including Fallbrook, Vista and Oceanside.

Rep. Bob Filner, D-San Diego, is being challenged by Republican David Lee Joy in the 51st Congressional District, which includes the South Bay cities of Chula Vista and National City along with the southern border of San Diego County and all of Imperial County.

The 53rd Congressional District is held by Rep. Susan Davis, D-San Diego. She is being challenged by Republican Michael Crimmins, a teacher and former military officer. The district stretches from Torrey Pines along the coast to the U.S.-Mexico border and east to Lemon Grove. It includes most of the city of San Diego.