user: Question: What is the sum of Round with a Position that is Center?
Columns: ['Round', 'Pick', 'Player', 'Position', 'College']
Types: ['real', 'real', 'text', 'text', 'text']
Sample row: [1.0, 28.0, 'Thomas Smith', 'Defensive back', 'North Carolina']
SQL:

assistant: SELECT SUM("Round") FROM "Table" WHERE "Position" = 'Center';