CONFLICT GND CRITICAL.

Narrative

MY CALL SIGN IS ATX X. I WAS CLRED INTO POS AND HOLD ON RWY 13L AT DAL. A WESTWIND HAD JUST LANDED AND WAS ROLLING OUT TO THE END OF THE RWY TO EXIT. AS I WAS TAXIING INTO POS; TWR CHANGED AN ACR Y JET FROM LNDG ON RWY 13R TO RWY 13L. TWR AND THE WESTWIND MADE SEVERAL CALLS BTWN THEN REGARDING THE JET WANTING TO EXIT AT THE END OF THE RWY. MEANWHILE; I'M SITTING AT THE START OF RWY 13L WHILE ACR Y CONTINUES ON FINAL APCH. I WATCHED THE WESTWIND JET CLR THE RWY AT THE END AND I EXPECTED TWR TO CLR ME TO TKOF. TWR NEVER CLRED ME TO TKOF; SO I CALLED AND REMINDED HIM I WAS STILL 'POS AND HOLD' AND ACR Y WAS SHORT FINAL. TWR SAID 'EXIT THE RWY IMMEDIATELY;' WHICH I DID AND ACR Y LANDED SHORTLY THEREAFTER. TWR SAID SOME EMERGENCY ON THE W SIDE OF THE ARPT REQUIRED THEIR ATTN AND THAT SIT CAUSED THE CTLR TO FORGET THAT I WAS CLRED ONTO THE RWY WHILE ACR Y WAS CLRED TO LAND. THE 737 WAS ONLY ABOUT 1/4 MI OUT WHEN I TURNED MY ACFT TO CLR THE RWY SINCE THE ACR Y PLTS NEVER CALLED TWR REGARDING MY ACFT STILL BEING ON THE RWY; I ASSUME THEY DID NOT KNOW I WAS EVEN THERE.