Who played Olivia Pope in 'Scandal'?

In which TV series is Harvey Specter a main character? Who played Mike Ross in 'Suits'? In which TV series is Mike Ross a main character? In which TV series is Rachel Zane a main character? Who played Hannah Horvath in 'Girls'? Who played Frank Underwood in 'House of Cards'? Who played Claire Underwood in 'House of Cards'? In which TV series is Claire Underwood a main character?