U.S. Sen. Barack Obama said Monday he accepted campaign contributions from Antoin "Tony'' Rezko without knowing that Rezko was a slumlord with problem buildings in the state Senate district Obama represented at the time. "Should I have known these buildings were in a state of disrepair? My answer would be that it wasn't brought to my attention,'' Obama, who's seeking the Democratic presidential nomination, said at a South Side campaign stop. His comments came in response to a Chicago Sun-Times report that he had done previously undisclosed legal work between 1995 and 1998 on a series of troubled low-income-housing deals...