user: Question: What is the sum of the round of the player who plays linebacker and has a pick # greater than 251?
Columns: ['Round', 'Pick #', 'Player', 'Position', 'College']
Types: ['real', 'real', 'text', 'text', 'text']
Sample row: [1.0, 26.0, 'Erik Flowers', 'Defensive End', 'Arizona State']
SQL:

assistant: SELECT SUM("Round") FROM "Table" WHERE "Position" = 'linebacker' AND "Pick #" > 251.0;