Nah, Bucky. He was dead since the Golden Age.The longest lasting death in comics was The Flash, Barry Allen, but they ruined that by bringing him back last year.
Sorry, Allyn, but that was a retcon introduced in 1963's Avengers #4.
Still, Bucky's death lasted longer than Allen's. It looks like Thomas and Martha Wayne have been dead the longest. Their murder was depicted in Detective Comics #33 (November, 1939), while Jor-L and Lora (later Jor-El and Lara) didn't appear until Superman #53 (August, 1948). A case can be made for the latter, though, since, not only had they appeared in unpublished material completed before Action Comics #1 (June, 1938), but baby Superman obviously had parents, and his departure from the exploding Krypton was shown in Action Comics #1.