Tricky SUBSTITUTE or REPLACE

What's the best way to swap the digits inside each cell of the L column?
That is, the first digit should be replaced by the second, and the second digit should be replaced by the first.
2-0 will be 0-2
2-1 will be 1-2
3-0 will be 0-3
3-1 will be 1-3
3-2 will be 2-3

EDIT: it think it can be done with IF

IF(L1="2-0","0-2", and then nested ifs for each case.. so I think I got it solved

Also on a sidenote, is there any easy way to automatically select the last 30/60 days from the date pickers? They are linked to cells T15 and T28 but if I change the dates in the cells manually I get an error, possibly because of the DATEVALUE in the date selection formula.

Thanks!