I rebuilt Ubuntu and I don't have my old SDK files. I used ~/.buildozer/android/platform/android-sdk-20/tools/android
in my terminal to try downloading them via the SDK manager (as seen in the picture shows) but I only see the SDK targeting APIs of 19 and lower.
I deleted the SDK inside of the .buildozer file, then changed android.sdk = 23
in buildozer.spec. It appears that buildozer automatically downloads the specified sdk.