CREATE TABLE "non_championship_race_results" (
  "num" real,
  "race_name" text,
  "circuit" text,
  "date" text,
  "winning_driver" text,
  "constructor" text,
  "report" text
);

Question: What date is listed at place 13
SQL: SELECT "date" FROM "non_championship_race_results" WHERE "num"=13;

Question: What date has a solitudering circuit
SQL: SELECT "date" FROM "non_championship_race_results" WHERE "circuit"='Solitudering';

Question: How many dates have silverstone circuit
SQL: SELECT COUNT("date") FROM "non_championship_race_results" WHERE "circuit"='Silverstone';

Question: How many constructors are listed for the XVI BRDC international trophy race
SQL: SELECT COUNT("constructor") FROM "non_championship_race_results" WHERE "race_name"='XVI BRDC International Trophy';