user: Question: Which round is a lower score than 21.5?
Columns: ['Round', 'Name', 'Song', 'Score', 'Status']
Types: ['text', 'text', 'text', 'real', 'text']
Sample row: ['Top 20', 'Shawn Tok 卓轩正', '林俊杰 - 翅膀', 24.0, 'IN']
SQL:

assistant: SELECT "Round" FROM "Table" WHERE "Score" < 21.5;