Well Mary, you can obviously say nineteen zero zero because nothing is wrong with saying and it means the same thing as nineteen double zero, nineteen hundred or one thousand nineteen hundred. But the much i know it is not used anywhere because it feels unnatural.

You say nineteen hundred.

I depends on context as well. For the year 1900, it would be extremely odd to say it any way other than "nineteen hundred". For the number 1,900 either "nineteen hundred" or "one thousand nine hundred" would be typical. For clarity (like an address for instance) it could also be said "one nine zero zero", though this would be less common in my experience.

You would normally say "nineteen hundred"