DOMA passed with veto-proof majorities so the only reason Clinton wouldn't sign it would be in support of the gay community, which would be incredibly unpopular in the 1990s.
Still, Clinton could pull out a win due to Dole being old, out of touch, and uncharismatic, in contrast to Clinton. The economy would put Clinton over the top too, I think.
President Bill Clinton/Vice President Al Gore: 44.28%, 277 Electoral Votes ✓
Fmr. Senator Bob Dole/Fmr. Secretary Jack Kemp: 43.74%, 261 Electoral Votes
Businessman Ross Perot/Economist Pat Choate: 10.62%, 0 electoral votes