Question: when did the first southern state secede from the union
[{'answer': 'December 20 , 1860', 'provenance': [{'wikipedia_id': '17832214', 'title': 'Secession in the United States', 'start_paragraph_id': 55, 'start_character': 111, 'end_paragraph_id': 55, 'end_character': 129, 'bleu_score': 1.0, 'section': 'Section::::Confederate States of America.\n'}]}]