Test 1
Test 2
*Plusle and Magnezone have the same stats in both replays.
Since with Ion Deluge Last Resort will be an Electric move, it's logical to think that Charge will double its power, but I went along and tested it just to make sure.
In the first replay Charge is used, and in the second it isn't. In test 2 Last Resort does significantly less damage, so we can deduce that Charge does affect Ion Deluged moves.
If you want to know exactly how powerful it is, then factoring in STAB and Charge, then the base power will be 420.