What is the highest Weight for the position of D, and the 1990–1991 Team was the chicago blackhawks?
CREATE TABLE "list_of_united_states_national_ice_hocke" (
  "position" text,
  "jersey_num" real,
  "name" text,
  "height_cm" real,
  "weight_kg" real,
  "birthdate" text,
  "birthplace" text,
  "1990_1991_team" text
);
SELECT MAX("weight_kg") FROM "list_of_united_states_national_ice_hocke" WHERE "position"='d' AND "1990_1991_team"='chicago blackhawks';