Which Japanese monarch had the longest reign?
{'directed': True, 'multigraph': False, 'graph': {}, 'nodes': [{'type': 'QUESTIONS_ENTITY', 'name_': 'Q17', 'id': 0, 'label': 'Japan'}, {'type': 'INTERNAL', 'name_': 'Q1137351', 'id': 1, 'label': 'Golden Week'}, {'type': 'ANSWER_CANDIDATE_ENTITY', 'name_': 'Q1355051', 'id': 2, 'label': 'Greenery Day'}], 'links': [{'name_': 'P17', 'source': 1, 'target': 0, 'label': 'country'}, {'name_': 'P527', 'source': 1, 'target': 2, 'label': 'has part(s)'}]}