Rep. Mike Castle (R) would begin a hypothetical 2010 Senate matchup favored over state Attorney General Beau Biden (D), according to a survey released this week by a Democratic polling firm based in Raleigh, N.C.But despite that bit of good news, Castle, who will be 71 in 2010, said he remains undecided about a Senate bid. “While it’s always nice to be ahead in the polls, they will not influence my decisions for the 2010 election,— he said in a statement released by his Congressional office. “I haven’t closed any doors on my political options, but at this time my priority remains the needs of our state and its representation in the House of Representatives.—The Public Policy Polling survey showed Castle leading Biden, the son of Vice President Joseph Biden, 44 percent to 36 percent. The automated survey of 782 Delaware voters was conducted March 5-8 and had a 3.5-point margin of error.Both Castle and the younger Biden held high job-approval ratings, according to the poll. Castle is a former governor and well-known moderate on Capitol Hill. Beau Biden is viewed as the most likely Democratic nominee in 2010, though he could face a primary challenge from former Lt. Gov. John Carney, who is also considering the possibility of running for Castle’s House seat.Other than Castle, public relations consultant Christine O’Donnell, the Republican nominee against Joseph Biden in 2008, is thinking of running for the Senate again.Sen. Ted Kaufman (D), a longtime Biden aide, was appointed to replace Vice President Biden in the Senate. But Kaufman has made it clear that he won’t seek a full Senate term in the 2010 special election.