1. On April 13, 1861, the first Ohio regiment answered President Abraham Lincoln's call for troops to defend the Union during the American Civil War. This marked Ohio's entry into the war and the beginning of its significant contribution to the Union war effort.

2. On April 13, 1930, the first flight with female pilots passed over Columbus. Ruth Nichols, who was a record-setting pilot and later a co-founder of Relief Wings, led the flight that also included Amelia Earhart.

3. On April 13, 1948, the groundbreaking ceremony was held for the Ohio Turnpike. The 241-mile-long highway that spans across the northern part of Ohio was completed three years later at a cost of $326 million.

4. On April 13, 1968, a major tornado outbreak occurred across Ohio, including the deadliest tornado in the state's history. The super outbreak of 47 tornadoes resulted in 10 deaths and 383 injuries.

5. On April 13, 2016, Democratic presidential candidates Hillary Clinton and Bernie Sanders faced off in a debate at the Ohio State University in Columbus. The debate covered issues such as healthcare, gun control, and foreign policy, and was one of the key moments in the 2016 presidential campaign.