What pins should I use when blinking AtTiny13 with arduino IDE?
You'll need an Arduino library that supports that chip, to make it appear in the Tools > Board list.  The library docs will tell you which pins then correspond to which Arduino digital I/Os. From that you can decide which pin to attach an LED to (with resistor) and how to edit the blink sketch.

Example: http://www.instructables.com/id/Pimp-Your-Chocolates-with-Arduino-IDE-and-ATtiny13/step2/Program-the-ATtiny13/