How to fetch current incumbent name for a Position_code/position id

Summary:

Please Help! Please share your insights ASAP!

I need help in fetching current incumbent name tagged to a position code.

I wrote the query like this :

SELECT

	DISTINCT HAPF.POSITION_ID AS INCUMBENT_POSITION_ID,

	(PPNF.first_name || ' ' || PPNF.last_name)AS "INCUMBENT_NAME"

	

from

	PER_PERSON_NAMES_F PPNF,

	PER_ALL_ASSIGNMENTS_M PAAM,

	HR_ALL_POSITIONS_F HAPF

	

WHERE 

	PPNF.PERSON_ID=PAAM.PERSON_ID

	AND HAPF.POSITION_CODE= 'xxxxxx' —used for testing

	AND SYSDATE BETWEEN PPNF.EFFECTIVE_START_DATE and PPNF.effective_end_date

	AND PAAM.POSITION_ID=HAPF.position_id

	AND SYSDATE BETWEEN PAAM.EFFECTIVE_START_DATE and PAAM.effective_end_date