I never heard of a left hand drill bit. In the picture it looks like the bolt is broken off a little below the flange. What I would do is use a dremel tool with a small grinding bit and carefully grind the top of the bolt flat. Be careful not to scuff the side's. Using the right size drill bit (test that it fits snug in your other hole) slowly and straight try to drill down just enough so the bit makes a nice center point in the hole. Switch to a pilot bit and drill through the bolt. Use tape on your drill bit so you don't go to deep. Switch back to the other bit and carefully drill out the rest. Now run a starter tap in the hole followed by a bottom tap. Don't be afraid, just go slow,steady, and straight. If you screw the hole up you can always use a heli coil repair kit. Good luck