CREATE TABLE table_78000 ("Class" TEXT, "GNRI No." FLOAT, "Name" TEXT, "BP serial No." FLOAT, "Rebuilt" FLOAT, "1958" TEXT, "Withdrawn" FLOAT)

What is the smallest withdrawn value with a GNRI greater than 172, name of Croagh Patrick and was rebuilt before 1939?
SELECT MIN("Withdrawn") FROM table_78000 WHERE "GNRI No." > '172' AND "Name" = 'croagh patrick' AND "Rebuilt" < '1939'
SELECT MIN("Withdrawn") FROM "table_78000" WHERE "GNRI No." > '172' AND "Name" = 'croagh patrick' AND "Rebuilt" < '1939'