You can only claim rent paid in Ontario.
Here is the quote from the ONBEN form itself:
Enter the
total amount of rent paid for your principal residence (including a private
long-term care home) in
Ontario for 2018
. (Do not enter rent paid for a principal residence that was not
subject to property tax.
If you lived
in a subsidized housing unit, you should check with your landlord to find out
if property tax was paid for the unit before entering an amount.)
