In my lifetime, as far as Presidents go.... Eisenhower and Trump had no experience in politics. Of those who had experience, Obama had the least. He was a state senator in Illinois (is that something to brag about?) for 5 years and a US Senator for 3. If you include campaigning, he actually had less than 3 years as a US Senator.
As far as qualifications, none of these three had the experience to do the job. Eisenhower did a wonderful job as President and is still highly regarded today. Trump has yet to serve a day in the office (and already has many people who hate him, unfortunately) but I remain hopeful. Obama spent 8 years complaining about the mess he was handed while doubling our debt, forcing health care on a disapproving public and polarizing our nation. I was hopeful when Obama was elected but my hope changed.