Question: when did oscar de la hoya fight chavez
[{'answer': 'June 7 , 1996', 'provenance': [{'wikipedia_id': '45497067', 'title': 'Julio César Chávez vs. Oscar De La Hoya', 'start_paragraph_id': 1, 'start_character': 114, 'end_paragraph_id': 1, 'end_character': 130, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '45497067', 'title': 'Julio César Chávez vs. Oscar De La Hoya', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 180, 'bleu_score': 0.934334813046729, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10109739845092893261}, 'section': 'Section::::Abstract.'}]}]