Partition By over Two Columns in Row_Number function, Sql Server

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create table t (aon_empl_id varchar(16), hr_dept_id varchar(16), Transfer_Startdate date, Effective_bdate date)
insert into t values 
 ('0100690','69895','01/01/2017','2017-01-01')
,('0100690','69895','01/01/2017','2017-01-03')
,('0100690','69895','01/01/2017','2017-01-04')
,('0200700','69895','01/01/2016','2016-01-01')
,('0200700','69895','01/01/2016','2016-01-03')
,('0200700','69896','01/01/2017','2017-01-04')
,('0200700','69896','01/01/2017','2017-01-04');

select top 1 with ties
     aon_empl_id
   , hr_dept_id
   , Transfer_Startdate = convert(char(10),Transfer_Startdate,120)
   , Effective_bdate    = convert(char(10),Effective_bdate,120)
 from t
 order by row_number() over (
       partition by aon_empl_id, hr_dept_id, Transfer_Startdate 
       order by Effective_bdate
     )

;with cte as (
    select
        rn = row_number() over (
          partition by aon_empl_id, hr_dept_id, Transfer_Startdate 
          order by Effective_bdate
        )
      , aon_empl_id
      , hr_dept_id
      , Transfer_Startdate = convert(char(10),Transfer_Startdate,120)
      , Effective_bdate    = convert(char(10),Effective_bdate,120)
    from t tw
    )

select *
    from cte
    where rn = 1

View schema
Execution time: 0,02 sec, rows selected: 6, rows affected: 7, absolute service time: 0,16 sec