That won’t work, openHABian only supports openHAB 2.X.
You can manually install openHAB 1.X on top of but will have to figure out how for yourself.
I’m sorry to tell but it would be really really bad advice to help you continue with 1.X
There will be no more support or fixes for 1.X. Here’s more info, but note I already wrote this 1,5 yrs ago, you’re overdue.
And don’t worry, things have improved a lot since so migrations work out rather smooth nowadays.
Note you do can continue using the KNX 1 binding (or any v1 binding) under OH2 without a need to change your KNX configuration and migrate that at a later point in time to the current v2 binding.
Check out the migration tutorial.