user: Question: What is the chassis when the rank is 3rd?
Columns: ['Year', 'Team', 'Chassis', 'Engine', 'Rank', 'Points']
Types: ['real', 'text', 'text', 'text', 'text', 'real']
Sample row: [2002.0, 'Mo Nunn Racing', 'G-Force', 'Chevrolet', '50th', 2.0]
SQL:

assistant: SELECT "Chassis" FROM "Table" WHERE "Rank" = '3rd';