CREATE TABLE table_13620 ("School" TEXT, "Location" TEXT, "Mascot" TEXT, "Enrollment" FLOAT, "IHSAA Class" TEXT, "# / County" TEXT)

What is the location where enrollment is 266 and and the county is 18 Delaware?
SELECT "Location" FROM table_13620 WHERE "# / County" = '18 delaware' AND "Enrollment" = '266'
SELECT "Location" FROM "table_13620" WHERE "# / County" = '18 delaware' AND "Enrollment" = '266'