Table schema:
CREATE TABLE table_1555308_1 (bleeding_time VARCHAR, platelet_count VARCHAR, prothrombin_time VARCHAR)

Question: How is the bleeding time wherein platelet count is decreased and prothrombin time is unaffected?
SQL: SELECT bleeding_time FROM table_1555308_1 WHERE platelet_count = "Decreased" AND prothrombin_time = "Unaffected"