CREATE TABLE table_11298 ("Year" FLOAT, "Title" TEXT, "Format" TEXT, "Studio" TEXT, "Release Date" TEXT, "Copyright Information" TEXT, "Catalog Number" TEXT)

What format is after 1991 and has a Catalog Number of 81868?
SELECT "Format" FROM table_11298 WHERE "Year" > '1991' AND "Catalog Number" = '81868'
SELECT "Format" FROM "table_11298" WHERE "Catalog Number" = '81868' AND "Year" > '1991'