What is the service chage of the boat howitzers with a 12-pdr light destination?
CREATE TABLE "table_of_dahlgren_boat_howitzers" (
  "designation" text,
  "bore" text,
  "weight" text,
  "service_charge" text,
  "range_yards" text,
  "number_made" real
);
SELECT "service_charge" FROM "table_of_dahlgren_boat_howitzers" WHERE "designation"='12-pdr light';