In terms of total increase in "federal debt to GDP" under U.S. presidents in the post-World War II era, Republican presidents during their terms have contributed far more to the debt load of the nation than Democrats.
Gerald Ford, Ronald Reagan, George H.W. Bush, and George W. Bush all added to the federal debt significantly on a percent of GDP basis. On the Democratic side, President Obama -- who inherited the worst financial crisis in this era from his predecessor -- also ranks high in terms of contributing to the federal debt as a percentage of GDP.
http://www.theatlantic.com/politics/...l-debt/264193/