=ARRAYFORMULA(QUERY({IFERROR(QUERY(IF(LEN(C2:C),
IF((C2:C<TODAY())*(D2:D<TODAY()), "Past",
IF((C2:C<TODAY())*(D2:D>TODAY()), "On Going now", )), ),
"where Col1='Past' or Col1='On Going now'"),"");
QUERY(IF(LEN(C2:C),
IF((C2:C>TODAY())*(D2:D>TODAY()), "Next Available", ), ),
"where Col1='Next Available' limit 1")},
"where Col1 is not null"))