CREATE TABLE table_54086 ("House Name" TEXT, "Composition" TEXT, "Named after" TEXT, "Founded" FLOAT, "Colours" TEXT)

When is the earliest year founded for houses named after the river benue?
SELECT MIN("Founded") FROM table_54086 WHERE "Named after" = 'river benue'
SELECT MIN("Founded") FROM "table_54086" WHERE "Named after" = 'river benue'