I doubt any democrat will win this next time. It'll be a republican, that's just the way in works. Very seldom has a new democrat or republican taken over as president from his/her same party. Odds are against it.
Teddy Roosevelt, 1904, after 8 years of Republican rule.
WH Taft, 1908, after 12 years of Republican rule.
H Hoover, 1928, after 8 years of republican rule.
FDR, 1940, after 8 years of Democratic rule.
FDR, 1944, after 12 years of Democratic rule.
Truman, 1948, after 16 years of Democratic rule.
Bush 41 1988, after 8 years of Republican rule.
Already happened 8 times in the last 108 years.
That's 8 out of 28 cycles, or: 28.57% of the time.
But here are the open cycles after at least eight years of one party's rule:
1904, 1908, 1912, 1920, 1928, 1940, 1944, 1948, 1952, 1960, 1968, 1976, 1988, 2000, 2008.
So, actually, it's 8 out of 15, or 53.33% of the time.
It's happened more than people realize.