Question: who has led the most laps at martinsville
[{'answer': 'Richard Petty', 'provenance': [{'wikipedia_id': '1719389', 'title': 'Martinsville Speedway', 'start_paragraph_id': 6, 'start_character': 166, 'end_paragraph_id': 6, 'end_character': 179, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '1719389', 'title': 'Martinsville Speedway', 'start_paragraph_id': 6, 'start_character': 0, 'end_paragraph_id': 6, 'end_character': 390, 'bleu_score': 0.8194479631454701, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 18238904960330585680}, 'section': 'Section::::History.\n'}]}]