Since entering the race for attorney general a year ago, Denise O'Donnell has labored to raise her profile in a campaign whose coverage has been largely fixated on two other Democratic candidates, Andrew M. Cuomo and Mark Green. But the political events of the last few days may have provided a boost to the candidacy of Ms. O'Donnell, a Buffalo resident who is the former United States attorney for the Western District of New York. Last week, Attorney General Eliot Spitzer selected David A. Paterson, a state senator from Harlem, to be his running mate in the 2006 governor's race....