user: Question: Which Best Actor has a Best Film of Mystery?
Columns: ['Year', 'Best Film', 'Best Director', 'Best Actor', 'Best Actress', 'Best Supporting Actress']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['2007 1st', 'The Host', 'Jia Zhangke for Still Life', 'Song Kang-ho for The Host', 'Miki Nakatani for Memories of Matsuko', 'No award']
SQL:

assistant: SELECT "Best Actor" FROM "Table" WHERE "Best Film" = 'Mystery';