According to Rudy Giuliani, Mary Matalin, and Dana Perino:
1/20/1993 to 1/20/2001: Bill Clinton
1/20/2001 to 9/10/2001: George W Bush
9/11/2001: Bill Clinton
9/12/01 to 12/21/2001: George W Bush
12/22/2001 (shoe bomb): Bill Clinton
12/23/2001 to 1/20/2009: George W Bush
1/20/2009 to 12/24/2009: Barack Obama
12/25/2009 to present: BARACK OBAMA! BARACK HUSSEIN OBAMA!!!!!!
Oh, and apparently, George Stephanopoulos too. But it's okay, because they're all serious people.