What is every GA if coach is Bob Ferguson and T is 6?
CREATE TABLE "table1_1888157_1" (
  "season" text,
  "league" text,
  "division" text,
  "gp" real,
  "w" real,
  "l" real,
  "t" real,
  "otl" real,
  "sol" real,
  "pts" real,
  "pct" text,
  "gf" real,
  "ga" real,
  "pim" real,
  "coach_es" text,
  "result" text
);
SELECT "ga" FROM "table1_1888157_1" WHERE "coach_es"='Bob Ferguson' AND "t"=6;