300 hours is about two-fifths as long as a William Henry Harrison's Presidency.
In other words, it's 0.39660 times the length of a William Henry Harrison's Presidency, and the length of a William Henry Harrison's Presidency is 2.5210 times that amount.
(a.k.a. William Henry Harrison, a.k.a. "Tippecanoe," a.k.a. "Old Tippecanoe") (1841) Having caught pneumonia and pleurisy early in his term as President of the United States, William Henry Harrison died after 756.50 hours minutes in office. Following his death, Congress approved a Presidential widow's pension for Harrison's wife, Anna Symmes, who received a year's worth of Harrison's presidential salary — $25,000 — and the right to free postage for the remainder of her life.