LONDON (Reuters) - Oil prices leaped back above $50 on Wednesday as President Bush (news - web sites) edged toward U.S. election victory, a result which traders said would bolster fuel demand and underpin anxiety over security of Middle East supply. U.S. light crude by 1230 GMT rose 63 cents to $50.25, reversing part of a 12 percent pull-back over the past week. Brent crude was up 57 cents at $47.12 a barrel. White House Chief of Staff Andy Card said Bush was convinced he has won re-election but will hold off a formal victory declaration to give Democrat John...