Query returns multiple rows where 1 row is expecte

I am running the following query to fetch the details of person enrolled in a plan. It is returning 2 rows where I expect only 1 row. Please can you suggest how I should filter the extra row.

select * from ben_prtt_enrt_rslt_f 

where person_id = <person_id value>

and pl_id = <pl_id value>