Question: who is the oldest jockey to win the kentucky derby
[{'answer': 'Shoemaker', 'provenance': [{'wikipedia_id': '340614', 'title': 'Bill Shoemaker', 'start_paragraph_id': 0, 'start_character': 5, 'end_paragraph_id': 0, 'end_character': 14, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '340614', 'title': 'Bill Shoemaker', 'start_paragraph_id': 12, 'start_character': 0, 'end_paragraph_id': 12, 'end_character': 542, 'bleu_score': 0.979054689945215, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 1639766202423697953}, 'section': 'Section::::Jockey career.\n'}]}]