user: Question: What's the highest round for a Defensive Tackle position?
Columns: ['Round', 'Pick #', 'Overall', 'Name', 'Position', 'College']
Types: ['real', 'real', 'real', 'text', 'text', 'text']
Sample row: [1.0, 22.0, 22.0, 'Anthony Castonzo', 'Offensive Tackle', 'Boston College']
SQL:

assistant: SELECT MAX("Round") FROM "Table" WHERE "Position" = 'Defensive Tackle';