Oracle 21c

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Create Table testpo ( 
  poid Varchar2(10),
  ToDelete Varchar2(10)
);
Insert into testpo values ('PO1', 'D');
1 rows affected

Insert into testpo values ('PO1', 'N');
1 rows affected

Insert into testpo values ('PO2', 'D');
1 rows affected

Insert into testpo values ('PO3', 'D');
1 rows affected

SELECT POID, MAX(TODELETE) as TODELETE
FROM testpo
GROUP BY POID


POID
TODELETE


PO1
N

PO2
D

PO3
D