What is the lowest 12-inch when the 13.5-inch/1250lb was 0, and the ship is seydlitz?
CREATE TABLE "hits_on_german_ships" (
  "ship" text,
  "13_5_inch_1400lb" real,
  "13_5_inch_1250lb" real,
  "12_inch" real,
  "total" real
);
SELECT MIN("12_inch") FROM "hits_on_german_ships" WHERE "13_5_inch_1250lb"=0 AND "ship"='seydlitz';