Pot for cooking long grained white rice on gas range
It depends on how much rice you're trying to cook. I rarely cook more than a few cups at a time, and I don't use a special pot for it (clad steel, though). Once the water comes to a boil, turn down to low, leave it for about 15 minutes (covered!), turn it off, wait another 15 minutes or so (still covered), and you're done.

If you're cooking a lot of rice at a time, a thick/heavy pot (enameled cast iron, or just a heavy clad steel pot) will help hold a low temperature without scorching the bottom of the rice.