Not really from a practical standpoint. No President or Governor would dare fail to pardon a man exonerated in court yet still sentenced to death, or it would be his career in the electric chair.
This is a matter of state law. The President can't pardon him, at least there is no legal precedent for him to do so.
EDIT: I stand corrected to the comment below.
Wikipedia has a much more thorough explanation than I can come up with right now (http://en.wikipedia.org/wiki/Pardon): In the United States, the pardon power for federal crimes is granted to the President of the United States under Article II, Section 2 of the United States Constitution states that the President "shall have power to grant reprieves and pardons for offenses against the United States, except in cases of impeachment." The Supreme Court of the United States has interpreted this language to include the power to grant pardons, conditional pardons, commutations of sentence, conditional commutations of sentence, remissions of fines and forfeitures, respites and amnesties.
http://www.npr.org/templates/story/story.php?storyId=1119362...
http://www.chicagotribune.com/news/chi-tc-nw-texas-execute-0...