Robert Bloch: "The Clown At Midnight", ROGUE, March 1960; collected in ROBERT BLOCH: APPRECIATIONS OF THE MASTER, edited by Richard Matheson and Ricia Mainhardt (Tor Books, 1995)

As reprinted in this fine anthology: (<a link to the essay in this volume online)

the paperback edition, 1995

Meanwhile, Ted White (writer and editor) notes that while Hamling credited himself as editor as well as publisher, he wasn't the one doing the editing, in his experience as a contributor:

Hamling was ROGUE's *publisher* but not its editor. In 1960 Frank Robinson was ROGUE's editor.  I know this because I sold my first article ("Riot at Newport") to ROGUE that year, and Frank whipped it into much better shape than I'd written it. Easily the best editor I've ever worked with. ("They're all your words, Ted. I just rearranged them.")  In 1959 Harlan Ellison was also an editor, but I think Frank was his superior. (In 1960 Harlan left ROGUE and moved back to NYC.)

As one can see below, the masthead of the magazine labeled Robinson and Ellison as "associate editors"...Hamling and Ms. Hamling were given supervisory titles...

Some folks, such as Eric Jamborsky, first saw the essay as reprinted in Forrest J Ackerman's Famous Monsters of Filmland magazine, apparently broken into two parts (over two issues?) in 1962, which "Garson O'Toole" notes at his Quote Investigator site.