CREATE TABLE table_15393 ("Operator" CLOB, "Shipyard" CLOB, "Project" CLOB, "Commissioned" CLOB, "Status" CLOB)

What is the commissioned for Vietnam?
SELECT "Commissioned" FROM table_15393 WHERE "Operator" = 'vietnam'
SELECT "Commissioned" FROM "table_15393" WHERE "Operator" = 'vietnam'