user: Question: Who placed fourth when the winner was Greg Hancock?
Columns: ['Round', 'Date', 'City and venue', 'Winner', 'Runner-up', '3rd placed', '4th placed', 'Results']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'April 24', 'Leszno , Poland Alfred Smoczyk Stadium', 'Jason Crump', 'Jarosław Hampel', 'Emil Sayfutdinov', 'Janusz Kołodziej', 'results']
SQL:

assistant: SELECT "4th placed" FROM "Table" WHERE "Winner" = 'Greg Hancock';