If column datatype is integer then leading zeros will be removed automatically but if the column datatype is varchar then leading zeros will not be removed while selecting data.

Create table #Rpt
(
  num varchar(100)
)

Insert into #Rpt(num)
Select '000000' union select 
'000001' union select 
'000010' union select 
'000100' union select 
'001000' union select 
'010000' union select 
'100000'  

Select query

select * from #Rpt

Leading Zero Example

Select query with removed leading zero

Select Replace(Ltrim(REPLACE(num,'0',' ')),' ','0') from #Rpt

Leading Zero Remove