CREATE TABLE table_18278508_2 (main_contestant VARCHAR2, co_contestant__yaar_vs_pyaar_ VARCHAR2)

Who performed with Tina Parekh?
SELECT main_contestant FROM table_18278508_2 WHERE co_contestant__yaar_vs_pyaar_ = "Tina Parekh"
SELECT "main_contestant" FROM "table_18278508_2" WHERE "Tina Parekh" = "co_contestant__yaar_vs_pyaar_"