Is this a quarantine boredom question or what?? lol
This Wed. is the 13th, next Wed. will be the 20th.
However... if you want to get technical, 'the next' Wednesday on the calendar would be this week on the 13th. But that's not the generally used reference, and if you said that probably nobody'd know what the heck you were talking about.
So I think it depends on the frame of reference and the purpose, but generally next Wed. (meaning next week's Wednesday) would be the 20th.
And people seem to be losing track of what day it is anyway so who knows what day any Wed. is!