Not quite. It was part of Russia from 1783 till 1918 (or so) then it was Part of USSR. But let's make it 1954 as you wrote, so it gives 171 years. Before 1783

Not quite. It was part of Russia from 1783 till 1918 (or so) then it was Part of USSR. But let's make it 1954 as you wrote, so it gives 171 years. Before 1783 Crimea was part of Ottoman Empire (Crimean Khanate), from about 1449. That makes 334 years. And before that Mongols ruled there from about 200 years. And even before it belonged partly to Kiev Rus' and Bizantium for another 300 years. So basing solely on the years (assuming that what you mean by historically) it looks like Crimea should go back to Turkey or split between Ukraine and Greece, surly not to Russia.