This depends on which accent you have

If your British... Harry Pottah!

If your American... Harree Podder!

Very accurate.

Ha-ry Pot-er

Hairy otter

Correction from above:

Most Americans pronounce it Hairy-Podder

Probably most British Hairy-Pottah

However you spell how draco pronounced it

I'm a brit and live in the US and it annoys me how these Americans say it

Haa-ree Poh-terr. ¯\_(ツ)_/¯