The television is a Bang & Olufsen 6-26. It does have red, white and yellow RCA inputs but according to the manual these are for temporary connections, such as a video camera.
Well, leaving an item plugged in shouldn't hurt. A composite signal from a video camera is the same as a composite signal from a DVD player, a VCR, a Roku 1, an HDMI converter, or any other composite output device.
But, on the back, you have a component input (AV3?). It's designed as component, with Red, Green, and Blue jacks. Here's the thing... some manufacturers make it as hybrid composite/component input. When that's the case (and I don't know if it is for that model TV) the component Green functions as composite Yellow. You could try connecting a composite device that way (yellow to green, video red and blue empty) and see what happens.