query is running very slow

Hi I am running this query on database version 11.2.0.2. Below is the sql for it.
INSERT INTO IHUB.TMP_SUPPLIES_PO
(
NEW_SCHEDULE_DATE,
ORDER_TYPE,
NEW_ORDER_QUANTITY,
NEW_ORDER_PLACEMENT_DATE,
FIRM_PLANNED_TYPE,
LINE_ID,
ORDER_NUMBER,
SUBINVENTORY_CODE,
ITEM_NAME,
ORGANIZATION_CODE,
SUPPLIER_NAME,
SUPPLIER_SITE_CODE,
COMMENTS,
ORIGINAL_NEED_BY_DATE,
PROMISED_DATE,
NEED_BY_DATE,
ACCEPTANCE_REQUIRED_FLAG,
UOM_CODE,
SR_INSTANCE_CODE,
DELETED_FLAG,
LAST_UPDATE_DATE,
LAST_UPDATED_BY,
CREATION_DATE,
CREATED_BY,
LAST_UPDATE_LOGIN,
REQUEST_ID,
PROGRAM_APPLICATION_ID,
PROGRAM_ID,
PROGRAM_UPDATE_DATE,
PROCESS_FLAG
)
SELECT DISTINCT F.DUE_DT AS NEW_SCHEDULE_DATE,