user: ### NOW ANSWER:
Question: what is the total sack when totaltk is 1 and asst. is more than 0?
Columns: ['Player', 'Tackles', 'Asst.', 'TotalTK', 'Sack', 'Yards', 'FumR']
Types: ['text', 'real', 'real', 'real', 'real', 'real', 'real']
Sample row: ['London Fletcher', 96.0, 37.0, 133.0, 0.5, 0.0, 1.0]
SQL:

assistant: SELECT SUM("Sack") FROM "Table" WHERE "TotalTK" = 1.0 AND "Asst." > 0.0;