Question: who does seth macfarlane play on american dad
[{'answer': 'Roger ( alien )'}, {'answer': 'Stan Smith ( father / husband )'}, {'provenance': [{'wikipedia_id': '908663', 'title': 'American Dad!', 'start_paragraph_id': 14, 'start_character': 0, 'end_paragraph_id': 14, 'end_character': 79, 'bleu_score': 0.8070557274927981, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12078885838869845940}, 'section': 'Section::::Cast and characters.:Main characters.\n'}]}]