user: Question: What is the lowest round for an Offensive Guard when the overall is smaller than 150?
Columns: ['Round', 'Overall', 'Player', 'Position', 'College']
Types: ['real', 'real', 'text', 'text', 'text']
Sample row: [1.0, 21.0, 'Reggie Nelson', 'Free Safety', 'Florida']
SQL:

assistant: SELECT MIN("Round") FROM "Table" WHERE "Overall" < 150.0 AND "Position" = 'Offensive Guard';