Question: who won the 2nd semi final of bgt
[{'answer': 'Andrew Johnston', 'provenance': [{'wikipedia_id': '17655688', 'title': "Britain's Got Talent (series 2)", 'start_paragraph_id': 2, 'start_character': 112, 'end_paragraph_id': 2, 'end_character': 127, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]