Попробуйте это:
/*
WITH PEOPLE (Name, Due_Date, Seq_Num) AS
(
VALUES
('Peter', '2020-03-01', '001')
, ('Peter', '2020-03-01', '002')
, ('Peter', '2020-03-02', '001')
, ('Paul ', '2020-03-03', '001')
, ('Paul ', '2020-03-03', '002')
, ('Paul ', '2020-03-04', '001')
, ('Paul ', '2020-03-04', '002')
, ('Mary ', '2020-03-05', '001')
, ('Mary ', '2020-03-05', '002')
)
*/
SELECT Name, Due_Date, Seq_Num
FROM
(
SELECT Name, Due_Date, Seq_Num, RANK() OVER (PARTITION BY NAME ORDER BY Due_Date DESC, Seq_Num DESC) MX_
FROM PEOPLE
)
WHERE MX_ = 1;