CREATE TABLE table_204_161 (id NUMBER, "name" CLOB, "1968 cf\ designator" CLOB, "place of\ manufacture" CLOB, "primary\ role ( s ) " CLOB, "service\ period" CLOB, "#\ used" NUMBER)

how many airco dh .4 's did the uk use in their period of service ?
SELECT "#\nused" FROM table_204_161 WHERE "name" = 'airco dh.4'
SELECT "#\nused" FROM "table_204_161" WHERE "name" = 'airco dh.4'