Phil Oliva was headed to a comfortable victory over Ken Del Vecchio in a Republican primary for New York's 18th Congressional District with minuscule turnout on Tuesday, giving him the party's nomination to go up against two-term Democratic Rep. Sean Patrick Maloney in November.Oliva was leading Del Vecchio by about 16 percentage points with the Putnam County tally finished and about 9 percent of the election districts yet to be counted in Orange, Westchester and Dutchess counties.