user: Question: What is the highest Weight for the position of D, anD the 1990–1991 Team was the Chicago Blackhawks?
Columns: ['Position', 'Jersey #', 'Name', 'Height (cm)', 'Weight (kg)', 'Birthdate', 'Birthplace', '1990–1991 Team']
Types: ['text', 'real', 'text', 'real', 'real', 'text', 'text', 'text']
Sample row: ['G', 35.0, 'Pat Jablonski', 188.0, 85.0, 'June 20, 1967', 'Toledo, Ohio', 'St. Louis Blues']
SQL:

assistant: SELECT MAX("Weight (kg)") FROM "Table" WHERE "Position" = 'D' AND "1990–1991 Team" = 'Chicago Blackhawks';