Question: who did clint howard play on andy griffith show
[{'answer': 'Leon', 'provenance': [{'wikipedia_id': '1371710', 'title': 'Clint Howard', 'start_paragraph_id': 6, 'start_character': 144, 'end_paragraph_id': 6, 'end_character': 148, 'bleu_score': 1.0, 'section': 'Section::::Career.:Television.\n'}]}, {'provenance': [{'wikipedia_id': '1371710', 'title': 'Clint Howard', 'start_paragraph_id': 6, 'start_character': 0, 'end_paragraph_id': 6, 'end_character': 547, 'bleu_score': 0.9627395327463101, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17759935628648916027}, 'section': 'Section::::Career.:Television.\n'}]}]