I went to NO DATA and caught missingno, and right after I caught it my game crashed. I reloaded in and I was still in NO DATA. My game then crashed again and I reloaded in only to find I was still in NO DATA. My game crashed once more. I have no clue how to get out of there.
I just spammed p and f12 until it got me back to the gaea town pokemon centre. Hope this helps.