Truman circa 1947
33rd President of the United States
In office
April 12, 1945 – January 20, 1953
I believe you are mistaken about Truman. He served almost eight years as president after the death of FDR. he was not eligible for reelection in 1952.
The 22nd Amendment was passed after Truman was elected, so it did not apply to him. (ex post facto)
He was eligible but chose not to run.