Question: who does sebastian stan play in once upon a time
[{'answer': 'Jefferson', 'provenance': [{'wikipedia_id': '9110929', 'title': 'Sebastian Stan', 'start_paragraph_id': 1, 'start_character': 162, 'end_paragraph_id': 1, 'end_character': 171, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]