Rather than looking at the sheer numbers, you should be looking at things as a constant flow. In terms of percentages, not only did Bush increase the national debt by nearly double what Obama did, he put the catalysts in play for a massive destabilization pattern in 2007 and 2008. In the first six years of his term, the deficit floated at around $400-500 billion a year, which is stupidly high already but simply seems to be the way things work. In 2007, 2008, and into 2009 (but excluding the Stimulus Act, because that was all Obama) he upped that number to $1.6 trillion. Overall, he added nearly $6 trillion to the national debt in his terms, a 100%+ increase, but the sharpest inclines occurred in those last couple of years.
Obama added more than $6 trillion to the national debt but he has sharply decreased the national deficit to *below* the $400-500 billion range that Bush held it in during his first term. Last year, the deficit was $327 billion, down from over $1 trillion in 2014. Including the $250 billion stimulus bill in 2009, Obama brought the budget down from a total of around $1.9 trillion in 2009 to $1.2 trillion in 2011, $672 billion in 2013, and the aforementioned $327 billion in 2015 (with a weird outlier in 2014 of $1+ trillion). That's a 56% increase, which is starkly lower than Bush's numbers despite the fact that Obama did the majority of the stimulus spending, passed healthcare, and generally lifted the economy. In actuality, he has been part of a movement to decrease spending, but he can't just make the deficit go away.
All that said, FDR increased the national debt during his terms by over 1000% in preparation for WWII. Woodrow Wilson increased the national debt by 700% - to a whopping $23.9 billion. Ronald Reagan increased the national debt by 188%. Even Bill Clinton, the guy who miraculously erased it all, added $1.3 trillion to the national debt, up 32% from HW Bush. The last surplus occurred under Eisenhower. FDR and Reagan, the two presidents who are idolized by the left and the right, both had a much sharper effect on the debt than Obama *and* Bush did.
All in all, this national debt talk is pretty much a wad of horse shit and there isn't a single person, Ron Paul and his brain child Gary Johnson included, who could get rid of the smell radiating from it.