Question: when did the old ebbit grill in washington dc open
[{'answer': '1856', 'provenance': [{'wikipedia_id': '20243540', 'title': 'Old Ebbitt Grill', 'start_paragraph_id': 4, 'start_character': 25, 'end_paragraph_id': 4, 'end_character': 29, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]