CREATE TABLE "league_cup" (
  "date" text,
  "round" text,
  "opponents" text,
  "h_a" text,
  "result_f_a" text,
  "attendance" real
);

Question: What is the sum of attendance for H/A values of "n"?
SQL: SELECT SUM("attendance") FROM "league_cup" WHERE "h_a"='n';