user: ### NOW ANSWER:
Question: Who won the mens singles when Lau Sui Fei won the womens singles?
Columns: ['Year Location', 'Mens Singles', 'Womens Singles', 'Mens Doubles', 'Womens Doubles']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['2012 Poznan', 'Wang Hao', 'Ding Ning', 'Kenta Matsudaira Koki Niwa', 'Cheng I-Ching Huang Yi-Hua']
SQL:

assistant: SELECT "Mens Singles" FROM "Table" WHERE "Womens Singles" = 'Lau Sui Fei';