I'm placing my O at the bottom-left position (2,0) for two important reasons:

1. Defensive: X currently has positions at top-right (0,2) and center (1,1). If X were to play at bottom-left (2,0), they would complete a diagonal and win. I need to block this threat immediately.

2. Offensive: By placing my O at (2,0), I'm also setting up a potential winning line along the left column, where I already have my first O at the top-left (0,0). This gives me a clear path to victory if I can later place my third O at middle-left (1,0).

This move both prevents X from winning and creates a winning opportunity for me in the next round.