“ State of Maryland is indistinguishable in principle from the present case; and we hold that it is applicable here although it was not decided until after the arraignment and trial in the instant case. ”

“ In February 1955 petitioner was arrested in connection with a recent homicide and attempted robbery. The next morning at a probable-cause hearing, but unassisted by counsel, he pleaded guilty to counts of murder and assault with intent to rob. Six days later at his arraignment, and again unaided by counsel, he pleaded not guilty to an indictment charging him with first-degree murder. After being assigned counsel for trial he took the stand in his own defense and again pleaded not guilty to the indictment, asserting instead that he lacked the premeditation necessary for first-degree murder. ”