DELETE
FROM TABLENAME
WHERE
(COLUMN_NAME IS NULL OR COLUMN_NAME = 0);

If you have additional columns containing NULL values and you want to refine your delete criteria

DELETE
FROM TABLENAME
WHERE
(COLUMN_NAME IS NULL OR COLUMN_NAME = 0) AND
(COLUMN_NAME_1 IS NULL OR COLUMN_NAME_1 = 0) AND
(COLUMN_NAME_2 IS NULL OR COLUMN_NAME_2 = 0) ;