In its two-hour debut, Paramount’s “The Untouchables” outperformed NBC’s Tuesday night lineup of “Quantum Leap” and “Reasonable Doubts” in L.A. and most other markets while continuing to improve time period performances.In L.A., the program ranked No. 2 in Nielsen and No. 3 in Arbitron on KCOP from 8-10 p.m. It fired off a 9.2 rating/13 share in Nielsen and a 8.8/12 in Arbitron. According to Nielsen, “The Untouchables” outdelivered previous perfs in the time period, improving a hefty 86% over the November 1992 movie average of a 5/7 . Paramount’s other new firstrun series, “Star Trek: Deep Space Nine,” continued to turn in impressive performances in its one-hour debut. Airing one time only at 10 p.m. on KCOP, the series finished first in its time period in Arbitron with a 10/16, but wound up No. 3 in Nielsen behind “Jack’s Place” (10.8) on KNBC-TV and the second half of the CBS movie (10.1) on KCBS-TV. KCOP placed a full-page ad in TV supplements to promote the unusual hour, but the L.A. Times incorrectly listed news in both its daily and weekly TV pages. The only network affil to carry “The Untouchables” in prime time, CBS’ WJBK-TV in Detroit, scored a 14.8/20, outperforming NBC’s Tuesday night block. Series also premiered Tuesday in Minneapolis, San Diego, Dallas and Cincinnati.