WASHINGTON - President Barack Obama is seeking a 12 percent budget increase for the Securities and Exchange Commission, including $382 million for more than 100 new enforcement staff to work on the agency's burgeoning caseload targeting fraud and market manipulation. Monday's request to Congress for nearly $1.3 billion for the SEC in the budget year starting Oct. 1 would boost total staff to 4,190 from the current 3,800 at the traditionally low-profile agency, which was rocked by its failure to detect the large 16-year fraud by money manager Bernard Madoff. The request includes a 10.6 percent increase in enforcement attorneys and investigators, to 1,368. The budget increase is notable because the administration's budget proposes spending cuts in programs outside of defense and security.