I think you are thinking to much for your regex
regexReplace($column1$,"[0]{1,}" ,"" )
or regexReplace($column1$,"^[0]{1,}" ,"" )
if you only want to match leading 0s
is enough
So basically you want to search for 0 or any character or character range in the search braket [ ]
You want to find 1 or more matches
and replace them with nothing
^=beginning of string