theory question

 In the accompaniment song LOA 3 there's a song called blues creepin' over me. If you look at the actual notes for the chord on the first measure, it is D,G,B on the G clef scale. but if you reference the Diatonic Harmonica note layout for an A harmonica, the draw holes are 3,2,and 1, which is B,E, and G#. From what I have studied in the past, a G note starts in the ring of the G clef. I am just using the 3 note chord as an example, but all of the notes in the song follow suit. If I play a 1 draw on the A harmonica and use a tuner, the note shows up as a B, but on the sheet music, the note shows up as a D as it is written. The second note on the G clef is a C, but on the tablature it shows a 4 blow, which is an A on a diatonic harmonica. Obviously the pattern continues with each note in the song. Am I missing something obvious here?