Going from Level 1 Germany, Level 2 Oberliga Nord, Level 3 Verbandsliga Niedersachsen, Level 4 Landesliga Niedersachsen Ost, Level 5 Bezirksliga Hannover, Level 6 Kreisliga Hannover.
If your local region is Niedersachsen, it means that you still need to check for each team/city, where it is placed in the regional divisions for level 4, 5 and 6. That’s quite a bit of work (which I noticed again when working on West Germany this weekend). Looking it up for each team via Wikipedia isn’t possible, so you need to make a map, combine teams, a lot of admin. Instead of you do it via level 6, the Kreislevel Wikipedia will tell you exactly where you are and going levels up is pretty easy to find.