Okay it took me a minute because I couldnt do it with a single formula. What I did was make logic statements in two colums. Either P1 is Z AND P2 is P OR P2 is P and P1 is Z. Then sorted by True in each column to count Zerg and Protoss wins in ZvP or PvZ.
Final tallies are 626 Zerg wins to 540 Toss wins. Total is 53.69% win rate ZvP.
Less than I found of ~55% when I did it about a month earlier but still slightly Z favored.
h ttp://www.sharecsv.com/s/36117a4093a6e92c0a0a687a64441914/MatchList%20sorted%20P1%20and%20P2%20Zerg%20and%20Toss%20wins.csv