Question: when was the first african american elected to congress
[{'answer': 'Hiram Rhodes Revels', 'provenance': [{'wikipedia_id': '391889', 'title': 'African Americans in the United States Congress', 'start_paragraph_id': 10, 'start_character': 479, 'end_paragraph_id': 10, 'end_character': 498, 'bleu_score': 1.0, 'section': 'Section::::History of black representation.:Reconstruction and Redemption.\n'}]}, {'provenance': [{'wikipedia_id': '391889', 'title': 'African Americans in the United States Congress', 'start_paragraph_id': 10, 'start_character': 0, 'end_paragraph_id': 10, 'end_character': 682, 'bleu_score': 0.9579655027162681, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15017031718435583821}, 'section': 'Section::::History of black representation.:Reconstruction and Redemption.\n'}]}]