user: Question: What is the highest Rd that Tom Sneva had the pole position in?
Columns: ['Rd', 'Name', 'Pole Position', 'Fastest Lap', 'Winning driver', 'Winning team', 'Report']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'Kraco Dixie 200', 'Rick Mears', '26.730', 'Gordon Johncock', 'Patrick Racing', 'Report']
SQL:

assistant: SELECT MAX("Rd") FROM "Table" WHERE "Pole Position" = 'Tom Sneva';