user: Question: What is the maximum pick when wr was the position and michigan the college, and the overall greater than 255?
Columns: ['Round', 'Pick', 'Overall', 'Name', 'Position', 'College']
Types: ['real', 'real', 'real', 'text', 'text', 'text']
Sample row: [8.0, 21.0, 203.0, 'Moses Denson', 'RB', 'Maryland Eastern Shore [o ]']
SQL:

assistant: SELECT MAX("Pick") FROM "Table" WHERE "Position" = 'wr' AND "College" = 'michigan' AND "Overall" > 255.0;