CREATE TABLE table_3108 ("No. in series" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "Production code" FLOAT)

What episode number in the series originally aired on February 28, 1992?
SELECT MIN("No. in series") FROM table_3108 WHERE "Original air date" = 'February 28, 1992'
SELECT MIN("No. in series") FROM "table_3108" WHERE "Original air date" = 'February 28, 1992'