Question: who is the shortest serving secretary of state
[{'answer': 'Elihu B. Washburne', 'provenance': [{'wikipedia_id': '19848208', 'title': 'List of Secretaries of State of the United States', 'start_paragraph_id': 4, 'start_character': 208, 'end_paragraph_id': 4, 'end_character': 226, 'bleu_score': 1.0, 'section': 'Section::::List of Secretaries of State by time in office.\n'}]}]