When Clinton won the White House in 1992, he only won 43% of the popular vote, the same amount won by Richard Nixon in 1968. Unlike President Nixon's reelection in 1972, Clinton did not win in a landslide but just short of getting 50% with just 49%. So the last double plurality popular vote wins was President Wilson. Whereas Clinton faced a three-way race in 1992 between the incumbent Republican President George Bush and independent businessman Ross Perot, eighty years prior Wilson faced a four-way race against the incumbent Republican President William Howard Taft, the Progressive Party, or Bull-Moose Party ran former president Theodore Roosevelt, and Socialist Party candidate Eugene Debs. Wilson won 41% of the popular vote and in his reelection bid four years later he came just as close to 50% as Clinton would 80 years later in 1996.
After Roosevelt 32, of the rest of the 20th Century Democratic presidents Johnson 36 and Jimmy Carter are the only other ones to receive more than 50% of the popular vote. In 1964, Johnson 36 won reelection in a landslide to the office he inherited through assassination. Then-former-Governor Carter got 50% of the popular vote in the super close 1976 election, not a mandate like Johnson 36's but 50%.
The first Democratic president elected in the 21st Century would be the first Democrat to win the presidency with more than 50% of the vote since Carter's win in 1976, and that would be Barack Obama in 2008. It would be with President Obama's reelection in 2012 that he would achieve what only two other Democratic presidents have achieved, winning over 50% of the popular vote in back-to-back elections. Andrew Jackson's two wins in 1828 and 1832 (there was also his plurality win, but of no matter to the House of Representatives in 1824) and FDR's 1932 and 1936 wins, as well as his 1940 and 1944 reelections to a third and fourth term, respectively.