CREATE TABLE table_31150 ("Name/ designation" CLOB, "Year of intro" FLOAT, "Country of origin" CLOB, "Primary cartridge" CLOB, "Major users" CLOB)

What country made the Flieger-Doppelpistole 1919?
SELECT "Country of origin" FROM table_31150 WHERE "Name/ designation" = 'Flieger-Doppelpistole 1919'
SELECT "Country of origin" FROM "table_31150" WHERE "Name/ designation" = 'Flieger-Doppelpistole 1919'