Question: who is the only president that has a ph.d
[{'answer': 'Woodrow Wilson', 'provenance': [{'wikipedia_id': '454303', 'title': 'List of presidents of the United States by education', 'start_paragraph_id': 25, 'start_character': 163, 'end_paragraph_id': 25, 'end_character': 177, 'bleu_score': 1.0, 'section': 'Section::::Graduate studies by type.:Law school.\n'}]}]