CREATE TABLE table_58198 ("Character" TEXT, "Portrayed by" TEXT, "Crime" TEXT, "First appearance" TEXT, "Last appearance" TEXT)

What is the name of the first appearance when Chad Williams is a portrayal?
SELECT "First appearance" FROM table_58198 WHERE "Portrayed by" = 'chad williams'
SELECT "First appearance" FROM "table_58198" WHERE "Portrayed by" = 'chad williams'