Question: who won the election for mayor in boston
[{'answer': 'Marty J. Walsh', 'provenance': [{'wikipedia_id': '53215864', 'title': '2017 Boston mayoral election', 'start_paragraph_id': 1, 'start_character': 147, 'end_paragraph_id': 1, 'end_character': 161, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'Marty Walsh'}, {'answer': 'Incumbent Democratic mayor Marty J. Walsh'}, {'provenance': [{'wikipedia_id': '53215864', 'title': '2017 Boston mayoral election', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 308, 'bleu_score': 0.908198718008664, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 1052055747680117372}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '39050635', 'title': 'Marty Walsh (politician)', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['Martin Joseph Walsh (born April 10, 1967) is an American politician from Boston, Massachusetts. A Democrat, he currently serves as the 54th Mayor of Boston, having served in office since 2014.', 'Martin Joseph Walsh (born April 10, 1967) is an American politician from Boston, Massachusetts. A Democrat, he currently serves as the 54th Mayor of Boston, having served in office since 2014.']}}]}, {'provenance': [{'wikipedia_id': '24437894', 'title': 'Boston', 'section': 'Section::::Government and politics.\n', 'start_paragraph_id': 111, 'end_paragraph_id': 111, 'meta': {'evidence_span': ["Marty Walsh became Mayor in January 2014, his predecessor Thomas Menino's twenty-year tenure having been the longest in the city's history.", "Marty Walsh became Mayor in January 2014, his predecessor Thomas Menino's twenty-year tenure having been the longest in the city's history.", "Boston has a strong mayor council government system in which the mayor (elected every fourth year) has extensive executive power. Marty Walsh became Mayor in January 2014, his predecessor Thomas Menino's twenty-year tenure having been the longest in the city's history."]}}]}, {'provenance': [{'wikipedia_id': '53215864', 'title': '2017 Boston mayoral election', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['The Boston mayoral election of 2017 was held on Tuesday, November 7, 2017, to elect the mayor of Boston, Massachusetts. Incumbent Democratic mayor Marty J. Walsh won re-election to a second term, defeating District 7 City Councilor Tito Jackson, and two long-shot candidates, Robert Cappucci and Joseph Wiley.', 'Incumbent Democratic mayor Marty J. Walsh won re-election to a second term, defeating District 7 City Councilor Tito Jackson, and two long-shot candidates, Robert Cappucci and Joseph Wiley.', 'The Boston mayoral election of 2017 was held on Tuesday, November 7, 2017, to elect the mayor of Boston, Massachusetts. Incumbent Democratic mayor Marty J. Walsh won re-election to a second term, defeating District 7 City Councilor Tito Jackson, and two long-shot candidates, Robert Cappucci and Joseph Wiley.']}}]}]