user: Question: What is the mean round number for center position when the pick number is less than 23?
Columns: ['Round', 'Pick #', 'Overall', 'Name', 'Position', 'College']
Types: ['real', 'real', 'real', 'text', 'text', 'text']
Sample row: [2.0, 23.0, 55.0, 'Peter Konz', 'Center', 'Wisconsin']
SQL:

assistant: SELECT AVG("Round") FROM "Table" WHERE "Position" = 'center' AND "Pick #" < 23.0;