Question: who represented the constitutional union party in the election of 1860
[{'answer': 'John Bell of Tennessee', 'provenance': [{'wikipedia_id': '648570', 'title': 'Constitutional Union Party (United States)', 'start_paragraph_id': 2, 'start_character': 482, 'end_paragraph_id': 2, 'end_character': 504, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]