To make pairs to $10$ you need to leave out $5$ and $10$, because you would need a double for the $5$ and a $0$ for the $10$.
To make pairs to $12$ you need to leave out $1$ and $6$, because you need $11$ for the $1$ and double for the $6$.
To make pairs to $13$ you need to leave out $1$ and $2$, because you need numbers higher than $10$ ($11$ and $12$) .
To make pairs to $11$ ... you don't need to leave ANYTHING out, because $11$ is an odd number so you don't need any doubles AND you don't need partners bigger than $10$.