user: Question: What is the highest overall pick that has c as the position, with an NFL Draft greater than 1977?
Columns: ['Player', 'Position', 'Overall Pick', 'Round', 'NFL Draft', 'Franchise']
Types: ['text', 'text', 'real', 'text', 'real', 'text']
Sample row: ['Ray McDonald', 'RB', 13.0, '1st', 1967.0, 'Washington Redskins']
SQL:

assistant: SELECT MAX("Overall Pick") FROM "Table" WHERE "Position" = 'c' AND "NFL Draft" > 1977.0;