Question: which u.s. president enacted the federal income tax system
[{'answer': 'Woodrow Wilson', 'provenance': [{'wikipedia_id': '1615034', 'title': 'Revenue Act of 1913', 'start_paragraph_id': 1, 'start_character': 331, 'end_paragraph_id': 1, 'end_character': 345, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]