It was a double-bill. Most sites say it was "War is Hell".
Following the horror in Dealey Plaza accused presidential assassin Lee Harvey Oswald (1939-1963) slipped into Dallas’ Texas Theatre without paying, immediately alerting authorities. A double feature was playing that day, "War Is Hell" (1963) starring Baynes Barron and Michael Bell and "Cry of Battle" starring Van Heflin and James MacArthur. The former was a Korean War film while the latter was set in the Pacific during World War II. The nervous Oswald, however, was unable to watch much of the twin bill as he was quickly arrested by Dallas Police following a brief, violent struggle.