user: Question: What year is Guard Mario Chalmers?
Columns: ['Name', 'Position', 'Height', 'Weight', 'Year', 'Home Town']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Darrell Arthur', 'Forward', '6–9', 230.0, 'Freshman', 'Dallas, TX']
SQL:

assistant: SELECT "Year" FROM "Table" WHERE "Position" = 'Guard' AND "Name" = 'Mario Chalmers';