For the race called by Marshall Cassidy, who was the host?
CREATE TABLE "1970s" (
  "year" real,
  "network" text,
  "race_caller" text,
  "s_host" text,
  "s_analyst" text,
  "reporters" text,
  "trophy_presentation" text
);
SELECT "s_host" FROM "1970s" WHERE "race_caller"='Marshall Cassidy';